1. Field of the Invention
The present invention relates to a process for the preparation of diarylethanes by reacting an aromatic with styrene in the presence of an acid heterogeneous catalyst at elevated temperatures and superatmospheric pressures.
2. Description of the Related Art
The preparation of diphenylethane by reacting an aromatic with styrene or with a styrene derivative is described in JP63-238028 (1988), where Y zeolites are used, in Polymer Journal 12 No. 6 (1980), 407, where Nafion, Amberlyst 15 or CF.sub.3 SO.sub.3 H is used, and in EP-A-421 340, where L zeolites are used. The syntheses described give usable yields only with the use of alkylated aromatics, but these yields are unsatisfactory. When the aromatic used is benzene, oligomers of styrene are predominantly formed.
It is an object of the present invention to remedy the abovementioned disadvantages.